D:\Work\testartifct>mvn clean
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building mymaven 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
Downloading: http://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-
clean-plugin/2.4.1/maven-clean-plugin-2.4.1.pom
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 21.663s
[INFO] Finished at: Thu Jul 05 22:50:42 CST 2012
[INFO] Final Memory: 2M/60M
[INFO] ------------------------------------------------------------------------
[ERROR] Plugin org.apache.maven.plugins:maven-clean-plugin:2.4.1 or one of its d
ependencies could not be resolved: Failed to read artifact descriptor for org.ap
ache.maven.plugins:maven-clean-plugin:jar:2.4.1: Could not transfer artifact org
.apache.maven.plugins:maven-clean-plugin:pom:2.4.1 from/to central (http://repo.
maven.apache.org/maven2): Connection to http://repo.maven.apache.org refused: Co
nnection timed out: connect -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e swit
ch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please rea
d the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginResoluti
onException
据说可能是配置文件里的代理设置有问题
估计还是自动下载插件的时候网络有问题。。。
你那里直接访问这个网址能访问到吗
http://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-site-plugin/3.0/maven-site-plugin-3.0.pom
要是不行就先把.m2文件删除（或者改个其他名），再执行你那命令那MVN再重新构建下。